42RH / A500 question

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MileHighDart

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Say your looking at a couple 42RH transmissions both from Dakota’s.
One is from a 3.9 V6 truck and the other is from a 5.2 V8 truck.
Is there really any difference between the two? Is the V8 one a better choice?
 
The V6 is likely 904 based AKA A500

The V8 is likely 727 based AKA A518

Easy to tell, look at the pan, look at the passenger side. If the pan has a big "bump" along the pass side it's a 727/ 518

On far left is 518, middle is older 727, and A500/ 42R is at right. Notice the bump in the side on the larger transmissions

trans.jpg


.............and that translates directly to the two pan gaskets below

727904gasket-jpg.jpg


Also make sure your transmission core is actually hydraulic and not electronic. Hydraulic has the usual backup/ park switch, and another 3 terminal connector for the lockup and OD. The electronic ones have a multi pin connector for the computer, I forget, 6--8 pins
 
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Take the one that came from the 5.2 and has a nice pan content.
(A bit of greyish paste and nice red fluid.)
I pulled mine from a front end crashed Dakota so I could be fairly sure the trans wasn't why it was there.
 
Both tranny's are from 88-91 Dakotas, only A500's were used those years for either engine.

Here's a couple pics, both are definitely A-500 transmissions, note the shape of the pan on passenger side.

s-l503.jpg


s-l1600.jpg
 
MileHighDart said:
Both tranny's are from 88-91 Dakotas, only A500's were used those years for either engine.
Click to expand...

I knew I was going to use a cable throttle pressure, so I cut all those brackets and posts off both sides.
Even those two bolt holes in the pic where that wire holder is went away.
 
Either one will work. Your going to rebuild it anyway. Use the good stuff red lining clutches and bands. Billet Servo pistons and reinforced struts.
In the end it will be stout.
Get Hands Torqueflite book.

upload_2017-10-14_18-27-45.jpeg


This will help with the front rebuilding.
Take the od with the new parts for it to a tranny shop that can press it apart and rebuild it for you.
 
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The OD is not that hard. I did mine with an HF hydraulic press. Found a YouTube vid on "how to make" a press fixture. What you need is something to get up above the hub so you can access the retainer ring. I got lucky--had a bucket of special tools / parts / unknown, and one of them was "built for the job"

Biggest problem is you need a junk shaft to align the splines. This is a heavier duty one, same thing

 
You can use the shaft from the trans you are working on, you just need to remember to assemble the overdrive unit first, so that shaft is available more easily.
I do the method 67Dart273 used also, and works well, and works safely.
 
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